Researchers analyzed data from more than 80,000 men and women in Sweden who were prescribed antipsychotic or mood-stabilizing drugs. Over three years, 6.5 percent of the men and 1.4 percent of the women were convicted of a violent crime.

Compared to when they were not on medication, violent crime fell by 45 percent among those who took antipsychotics and by 24 percent among those who took mood stabilizers, according to the research, which was published online May 8 in The Lancet.

The two types of medications are often used together, but there was no evidence that prescribing both medications at once led to any greater reduction in violent crime, the researchers said. They also noted that mood stabilizers were associated with reductions in violent crime only among men with bipolar disorder.

Even though antipsychotic and mood-stabilizing drugs are widely seen as treatments for schizophrenia and bipolar disorder, many people in the study were prescribed these drugs to treat other conditions, such as depression and alcohol or drug abuse.

"Patients with psychiatric disorders are at risk of perpetrating violent acts, as well as being victims," study leader Dr. Seena Fazel, of Oxford University in England, said in a journal news release. "Until now, we have not known whether antipsychotics and mood stabilizers reduce risks of violence."

"By comparing the same people when they are on medication ... to when they are not, our study provides evidence of potentially substantial reductions in risk of violence, and suggests that violence is to a large extent preventable in patients with psychiatric disorders," Fazel added.